117,805 research outputs found
Development and integration study of a new front-end electronics for the upgrade of the Resistive Plate Chamber detector for high radiation environment
No full textThe Resistive Plate Chamber (RPC) is a gaseous detector that, by means of a gas mixture as sensing material, reveals the passage of ionizing particles. Two resistive parallel planar electrodes are the basic RPC structure. The applied high voltage generates a strong electric field within the gas, providing directly an avalanche multiplication as soon as a free electron is generated, leading to the absence of any drift time. This unique feature makes it suitable for timing measurements. Moreover, the simple structure and the low cost materials allow its usage for large area applications. The upgrade of the Resistive Plate Chamber detector for the operation in high-background environments consists in the reduction of the operating voltage along with the capability to detect signals as small as 100 μV , moving part of the detector amplification to the Front-End electronics. A new Front-End (FE) electronics has been developed in this thesis project to reach this goal, exploiting a BJT-based preamplifier and a fast discriminator in SiGe BiCMOS technology to improve the detector time resolution and increasing its rate capability. The preamplifier, coupled to the 1-mm gap RPC, has a very low noise (1000 e − rms) and a peaking time of 100 ps. The discriminator has Time-Over-Threshold (TOT) measurement capability and a linear threshold response for signals as fast as 1 ns. The minimum effective threshold on the RPC signals, achievable by this system, is ∼ 100 μV . These RPCs represent a new generation of large area timing detectors, which integrate for the first time a highly performing FE electronics, granting a record time resolution of ∼ 350 ps on a single gas gap of 1 mm with 1.2 mm electrodes thickness. The entire development of this new FE electronics along with the detailed study of the FE integration within the RPC detector will be illustrated in this thesis. Moreover, the results of this new generation of RPC detectors will be shown, particularly in terms of charge threshold achieved (∼ 3 pC) by the electronics and, consequently, the improved detector rate capability (∼ 10 kHz/cm2 ). Furthermore, the application of this newly developed FE electronics is reported, precisely within the ATLAS experiment. The architecture of the present ATLAS Muon Spectrometer (MS) has been designed for a luminosity of 1034 cm−2 s −1 with a security factor of 5 with respect to the simulated background rate, now confirmed by the LHC Run 1 results. Since HL-LHC will have a 5 times higher luminosity and a one order of magnitude bigger background, the demand in terms of performance increases, being the detector operated in a much harsher conditions. The BI-BIS78 projects are part of the LHC Phase-1 and Phase-2 approved upgrades, in order to ensure the demands coming from the physics for the next 20 years. They consists in the installation of an entire new layer of RPC detectors inside the Inner Barrel of the ATLAS experiment. This will ensure higher redundancy and robustness of the trigger system, almost complete acceptance and an improved momentum selectivity. The BIS78 upgrade, scheduled for LHC Phase-1, is the pilot project for the BI RPCs installation. It aims at the installation of 10% of the BI RPCs in the transition region between the endcap and the Inner Barrel of 5 6 CONTENTS ATLAS experiment. This barrel region is the one with the highest background and for this reason is an excellent test bench for the BI upgrade. The BIS78 position will also help in the reduction of the fake muons produced upstream with respect to the cryostats. The BI RPCs represent a new generation of RPCs, basing their largely improved performance on the new and highly performing FE electronics. The BIS78 project, along with the performance achieved by such RPCs, will be shown in this thesis work
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Square Dancing with the Stars to Enhance Dynamic Hirschman Linkages?
No full textIn this Presidential Address, the author takes the reader on a reconnaissance of his life and time as a regional scientist. He points out scenery he found scintillating along the way, hoping that some may pick up the banner and chew on a few of the ideas for a while. He suggests a revisit to Albert O. Hirschman’s notion of key sectors and more empirical analysis related to Marcus Berliant’s and Masahisa Fujita’s notion of knowledge creation and transfer.Presidential Address, San Antonio, Texas, March 29, 2014 (53rd Meetings of the Southern Regional Science Association
Appropriate Similarity Measures for Author Cocitation Analysis
No full textWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Development of an innovative device for high performance tracking measures
No full texthi this paper we present a new Weighting Resistive Matrix (WRM) capable of working for a CCD output. The basic idea is that the luminosity of the pixels defines the position error of the pixel itself. In order to reach this outcome, a variable dispersion is performed. A simple way to obtain this is to vary the dispersion width as a function of the input signal's frequency, proportional to the luminosity of the pixel. This is achieved adding a capacitor to the WRM cell. This new design is capable of performing the straight line fit with a variable position error, as a function of the luminosity
Letter from unknown writer to Jesse L. Boyce
No full textLetter to Jesse L. Boyce from unknown author (possibly Jack) about the investigation into the powder magazine located in the Grand Canyon. Some personal news is included in the letter such as the writer's marriage to the daughter of C.A. Taylor, former Supervisor of Cochise County
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Sarah L. Blum Author Visit - Warrior Nurse: PTSD and Healing
No full textHear Sarah L. Blum, author of Women Under Fire: Abuse in the Military, discuss her newest book, Warrior Nurse: PTSD and Healing followed by a Q&A and book signing.
Sarah L. Blum is a decorated Vietnam veteran who served as an operating room nurse during the intense fighting of 1967. In recognition of her service, she was awarded the Army Commendation Medal.
Sponsored by CWU Veterans Center and CWU Libraries.https://digitalcommons.cwu.edu/libraryevents/1252/thumbnail.jp
Lillian L. Lambert, Author, Speaker, and Entrepreneur
No full textLillian L. Lambert, Author, Speaker, and Entrepreneu
Letter to Alfred L. Shoemaker, February 10, 1948
No full textA handwritten letter from an unknown author addressed to Alfred L. Shoemaker, dated February 10, 1948. Within, the author discusses the Pennsylvania Dutch word for Ash Wednesday, along with traditions associated with this day.https://digitalcommons.ursinus.edu/shoemaker_documents/1118/thumbnail.jp
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